The present bicycle saddles generally have the following two structures:
(1) a structure comprising a polypropylene liner, laminated thereon an open pore polyurethane foam and a polyurethane/PVC outmost layer; or
(2) a structure comprising a polypropylene liner and an integral (surface pore closed) polyurethane foam.
The polypropylene liner is used for support load and resistance to impact, while the polyurethane outmost layer is for softness, comfortability and resistance to wear. During manufacturing, at first, the polypropylene and polyurethane are generally formed into a required shape, respectively, and then they are adhered together. To improve the adhesion, the surface of the polypropylene liner must be surface treated for coarsening or by, for example, flame, etc.
There are the following deficiencies in the bicycle saddles made in such a process:
1. Due to the manual operation, the surface treatment of the polypropylene liner is hardly completely carried out, resulting in the liner and the polyurethane not being sufficiently adhered, and, in turn, resulting in high rejection rate. In addition, the productivity of producing the saddle is low;
2. On using for a period of time, the saddles made by adhering polypropylene liner and polyurethane foam may be adhesion failure at the bottom thereof as a result of abrasion between the saddle and the leg of rider, shortening the duration thereof;
3. Besides the cost, the use of adhesive may cause problems on environment;
4. With the increase in the awareness of environmental protection and the increasing sternness of the environmental laws, provisions aiming at “producers being responsible for recycling and treatment” have been enacted in many countries, namely, the producers are required to recycle and treat waste plastics (including plastic saddles). Presently, the recycle of saddles includes splitting the polypropylene liner from the polyurethane outmost layer, and then respectively treating same. Such a method is difficult to carry out mechanically in large-scale. In addition, a great deal of labor and resources are requires, for example, in the split procedures, thus increasing the cost of production.
One object of the present invention is to resolve the above mentioned technical problem that exists for a long time, substituting the polypropylene containing material with a polyurethane composite, thus simplifying the producing process, increasing the productivity and qualification rate, and avoiding the use of adhesive to reduce the environmental problems caused thereby.
Another object of the present invention is to provide a process for producing said polyurethane composite, which is free of the deficiencies brought about by the manual operation during the surface treatment of polypropylene materials.
A further object of the present invention is to provide usage of the polyurethane composite in producing bicycle saddles and decorative materials.